Memory devices have been widely utilized in many applications. In various applications, the memory devices include a volatile memory and a non-volatile memory that is applicable for long term data storage. For example, the non-volatile memory includes the non-volatile memory includes an eFuse, an electrically-erasable programmable read-only memory (EEPROM), a flash memory, or a magneto resistive random-access memory (MRAM). A robust reference scheme is required to adequately read data stored in memory cells of the non-volatile memory.